KR20220082311A - A method for correcting errors in 3d printing - Google Patents

Abstract

A method for correcting errors in 3D printing is disclosed. The method for correcting the error of the 3D printing includes: a) calculating cross-sectional area data for an arbitrary layer of the printing object by a computer system from original digital data of the printing object that can be decomposed into a stacked structure of a plurality of slices; b) calculating output cross-sectional area data for an output operation of a 3D printer from the calculated cross-sectional area data; c) correcting an error of the output cross-sectional area data by applying a data correction algorithm to the calculated output cross-sectional area data; d) calculating the output cross-sectional area data in which the error is corrected by applying the data correction algorithm; and e) performing an output operation of the 3D printer based on the output cross-sectional area data for which the calculated error is corrected.

Description

A METHOD FOR CORRECTING ERRORS IN 3D PRINTING

The present invention relates to a method for correcting an error in 3D printing, and more particularly, to an error correction method and apparatus capable of improving the precision of a 3D printer output.

A 3D printer is a device that creates a physical model just like printing three-dimensional mechanical parts from a computer file designed with a CAD program. Such a 3D printer converts a modeled 3D shape through software such as a CAD system into slice data divided into a plurality of thin cross-sectional layers, then uses it to form a plate sheet, and stacks it to complete the sculpture.

In general, a 3D printer produces a three-dimensional object by outputting and laminating a material (usually, ABS resin) to an output bed through a nozzle supported by an extrusion head. The bed moves in the three directions of X, Y, and Z in the Cartesian coordinate system with respect to the extrusion head or in some directions (some products have the extrusion head moving), and the resulting material is deposited at a predetermined position on the bed. In the movement of the bed, the movement in each axial direction is precisely controlled by a screw or the like connected to the bed, so that the produced material is stacked at the correct position. However, the process of producing a result through this resin lamination is made at a high temperature, and the bed moves a lot during one operation or receives an external force by an extrusion head.

The X, Y, and Z axes of the 3D printer are greatly affected by the weight and gravity of the printout, and accordingly, the flatness may not be aligned because the axis sags or the bed is tilted with respect to the horizontal axis. When such a situation occurs, problems such as overlapping layers or damage to the bed by the nozzle may occur. Therefore, a leveling operation that aligns the straightness and the bed level with respect to the X, Y, and Z axes of the 3D printer must be preceded.

In the conventional system for measuring the error of the axis of a 3D printer, a single spot is obtained using a laser beam and the error is confirmed by measuring the displacement of the single spot, so it is difficult to accurately measure the error. In addition, in the conventional method of correcting the axis of the bed, a method in which the user measures the inclination of the bed and physically moves the bed itself to adjust the level was used. However, the above method is a method in which the operator directly adjusts the mount height of the bed using a wrench, and has an advantage in that the level of the bed can be corrected by a simple structure due to the nature of the desktop 3D printer. There is a problem that the molding error of the printed product increases.

An object of the present invention for solving the above problems is to provide a method for correcting an error of 3D printing.

The present invention for achieving the above object provides a method for correcting an error of 3D printing.

The method for correcting the error of the 3D printing includes: a) calculating cross-sectional area data for an arbitrary layer of the printing object by a computer system from original digital data of the printing object that can be decomposed into a stacked structure of a plurality of slices; b) calculating output cross-sectional area data for an output operation of a 3D printer from the calculated cross-sectional area data; c) correcting an error of the output cross-sectional area data by applying a data correction algorithm to the calculated output cross-sectional area data; d) calculating the output cross-sectional area data in which the error is corrected by applying the data correction algorithm; and e) performing an output operation of the 3D printer based on the output cross-sectional area data for which the calculated error is corrected.

In calculating the cross-sectional area data in step a), 2D drawing data for the layer is generated in order to extract 2D data for the arbitrary layer by the computer system.

In calculating the output cross-sectional area data in step b), the output cross-sectional area data is classified according to the printing method to be actually output.

The printing method is SLA (Stereolithography Apparatus).

In correcting the error of the output cross-sectional area data by applying the data correction algorithm in step c), in the case of an image moving away from the inside according to the inside and outside positions generated through the division between the inside and the outside of the 2D image, preset An image that is close to the inside by one distance is created, and in the case of an image that gets closer to the inside, it is created as an image that is farther from the inside by a preset distance.

When using the method for correcting the error of 3D printing according to the present invention as described above, the cross-sectional area data of the printing object is calculated from the original digital data, and the output cross-sectional area data for the output operation of the 3D printer is calculated based on the cross-sectional area data. The precision of the 3D printer output can be improved by calculating, applying a data correction algorithm to the output cross-sectional area data, correcting the error of the output cross-sectional area data, and finally performing the output operation of the 3D printer according to the corrected output cross-sectional area data. There are advantages that can be

1 is a diagram schematically showing the configuration of an image processing system employed to implement an image processing method for error correction of a 3D printer output according to the present invention.
2 is a flowchart illustrating an execution process of an image processing method for correcting an error of a 3D printer output according to an embodiment of the present invention.
3 is a diagram schematically showing an error corrected and output during data output for sectional data extraction and output according to the method of the present invention.
4 is a diagram schematically illustrating a process of extracting output cross-sectional area data from an image file (source data) and correcting it by applying a data correction algorithm.
5 is a diagram schematically illustrating a process of calculating the cross-sectional area data from source data and calculating the output cross-sectional area data from the cross-sectional area data.
6 is a diagram schematically illustrating a process of correcting the output cross-sectional area data by applying a data correction algorithm to the output cross-sectional area data.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements.

Terms such as first, second, A, and B may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram schematically showing the configuration of an image processing system employed to implement an image processing method for error correction of a 3D printer output according to the present invention.

Referring to FIG. 1 , an image processing system 100 employed for implementing an image processing method for error correction of a 3D printer output according to the present invention includes a computer system 110 and a 3D printer 120 . .

The computer system 110 is provided with a memory in which original digital data for a printing object is stored.

In addition, the computer system 110 calculates cross-sectional area data for an arbitrary layer of the printing object from the original digital data (source data) of the printing object, and also for the output operation of the 3D printer 120 from the calculated cross-sectional area data An application for calculating the output cross-sectional area data is loaded. In addition, the computer system 110 is equipped with a data correction algorithm (a kind of software program) for correcting an error between the calculated output cross-sectional area data and the initial cross-sectional area data calculated from the original digital data (source data).

Then, based on the image processing system having the above configuration, an image processing method for correcting an error of a 3D printer output according to the present invention will be described.

2 is a flowchart illustrating an execution process of an image processing method for correcting an error of a 3D printer output according to an embodiment of the present invention.

Referring to FIG. 2 , the image processing method for error correction of the 3D printer output according to the present invention is based on the image processing system 100 including the computer system 110 and the 3D printer 120 as described above. A method of processing an image for error correction of a 3D printer output by a computer system 110, by first using the computer system 110 from original digital data (source data) of a printing object that can be decomposed into a stacked structure of a plurality of slices Cross-sectional area data for an arbitrary layer of the printing object is calculated (step S201). Here, in calculating the cross-sectional area data, 2D drawing data for the corresponding layer may be generated in order to extract 2D data for the arbitrary layer by the computer system 110 . This will be explained again later in this regard.

When the cross-sectional area data is calculated from the original digital data (source data) in this way, the output cross-sectional area data for the output operation of the 3D printer 120 is calculated from the calculated cross-sectional area data (step S202). This will be described again later. Here, in calculating the output cross-sectional area data, the 2D drawing data (2D drawing image file) may be directly imaged or an output file corresponding to the image may be generated. In this case, in the case of the 2D drawing image file, the output cross-sectional area data may be a 2D image file, and in the case of the drawing output file, the output cross-sectional area data may be movement path coordinate data on which the laser actually moves.

In addition, in calculating the output cross-sectional area data, the output cross-sectional area data may be classified according to a printing method that is actually output. In this case, the printing method may include at least one of Digital Light Processing (DLP), Stereolithography Apparatus (SLA), and Fused Deposition Modeling (FDM).

When the output cross-sectional area data is calculated as described above, an error in the output cross-sectional area data is corrected by applying a data correction algorithm to the calculated output cross-sectional area data (step S203). That is, the error between the calculated output cross-sectional area data and the original cross-sectional area data calculated from the original digital data (source data) is corrected. Here, in correcting the error of the output cross-sectional area data by applying the data correction algorithm, in the case of an image moving away from the inside according to the inside and outside positions generated through the division between the inside and the outside of the 2D image, a preset distance An image close to the inside is created, and in the case of an image getting closer to the inside, it can be generated as an image moving away from the inside by a preset distance.

When the error correction is completed in this way, the output cross-sectional area data for which the error is corrected by application of the data correction algorithm is calculated (step S204).

Then, the output operation of the 3D printer 120 is performed based on the output cross-sectional area data for which the calculated error is corrected (step S205).

Hereinafter, in relation to the image processing method for correcting the error of the 3D printer output according to the present invention as described above, an amplified description will be made.

3 is a diagram schematically showing an error corrected and output during data output for sectional data extraction and output according to the method of the present invention.

Referring to FIG. 3 , a black part is a part where an actual output is generated when output data is extracted for outputting a curved image as shown in (A). In this case, in the case of External 1, a phenomenon in which the inner part (the part forming the boundary with the External 1 region) is output larger toward the external 1 region occurs compared to the desired size for the actual output. Also, in the case of the outer 2, a phenomenon that the inner portion (the portion forming the boundary with the outer 2 area) is output smaller from the area of the outer 2 toward the inner area occurs compared to the size for which the actual output is desired. Accordingly, in the method of the present invention, the output cross-sectional area data is output by correcting such an error.

That is, referring to FIG. 3B , the 2D sliced image for actual output is expressed in black. At this time, before deriving the value of the actual output data, the image is changed like the line marked in red to obtain an output with a small deviation (error) value from the original digital data when extracting data. In the case of a straight line and a curved line during actual output, a difference in the size of the output occurs, and a difference in the size of the output occurs depending on the drawing path of the output. When extracting data for output, it is possible to reduce the deviation (error) between the original digital data and the final output by discriminating the inside and the outside to distort the output image (that is, through data correction).

4 is a diagram schematically illustrating a process of extracting output cross-sectional area data from an image file (source data) and correcting it by applying a data correction algorithm.

Referring to FIG. 4, when extracting a slice data drawing as shown in (B) from a cylindrical STL (stereolithography) file in which one direction is deleted from the cylinder of the image as shown in (A), an image such as a 2D image can be extracted. be able to

In the case of the existing slice algorithm, the movement coordinates called "G-code" and the movement arrangement are extracted from the 2D drawing information to the movement path of the equipment that the actual milling machine/3D printer moves and outputs (see FIG. 5). In this case, the extracted data values may be represented in the form of a vector array. In the form of a vector array, by dividing the inner part and the outer part (when the position of the vector start point moves from the top to the right, the right direction is set to the inside and the left direction is set to the outside based on the vector progress direction) will proceed And according to the divided inner and outer parts, functions for inside and outside are added to correct the pattern drawing the entire outside.

5 is a diagram schematically illustrating a process of calculating cross-sectional area data from source data and calculating output cross-sectional area data from cross-sectional area data.

Referring to FIG. 5 , an infill part 501 is a pattern for drawing a sliced inside of the extracted "G-code" as an infill part. And the inset part 502 is a pattern for drawing the outside sliced by the inset X part of the extracted "G-code". This indicates the number of edges of the sliced data. In addition, the inset0 part 503 is an inset0 part (outermost data among sliced data) of the extracted "G-code", and is a pattern for drawing the outermost slice of the data.

6 is a diagram schematically illustrating a process of correcting the output cross-sectional area data by applying a data correction algorithm to the output cross-sectional area data.

Referring to FIG. 6 , first, G code data of a sliced image is extracted for vector operation preparation. Then, the extracted Inset0 data vector table is configured in the form of a double array.

The primary array consists of the array start points of Inset0, and displays one closed structure coordinate area (the same position as the start and end points) in the secondary array. In the drawing in which the number of primary arrays is sliced, Inset0, that is, the movable outermost coordinate value is displayed. Among the values of each movement coordinate (secondary array included in the primary array) in each primary array, the uppermost coordinate value among the Y-axis coordinate values is selected. Based on this value, the inner and outer regions are divided according to the moving direction. At this time, when moving to the left in the uppermost coordinate, the left side of the moving direction becomes the inner area, and when moving to the right, the right side of the moving direction becomes the inner area.

When the inner and outer directions are distinguished, additional calculations for changing the image are performed according to the alpha value and the angle of each vector. At this time, the calculated values of the new movement coordinates are stored in the form of a newly changed data array having the same array size.

After performing the above operation on the primary array, the performed primary array is excluded from calculating the next value, the Y vector array of the next rank is found, and the coordinate value is within/in the region of the primary array excluded. Determine if it is an external value. At this time, the inside/outside change is performed according to the inside/outside of the area. After determining the inside/outside of the area, if the value is inside the excluded primary array, the coordinate movement setting value is changed according to the movement coordinate value, and in the case of outside the area, the same operation as performing the excluded primary array is repeated again do.

When the above series of processes is performed and the operation is performed until there is no value in the primary array, the entire slice data change is completed.

In FIG. 6 (A), the value of the G vector is changed according to the angles of the initial two vectors (A, B), and in this case, it can be expressed as A = F' + G. In (B), the value of the G' vector is changed by the angle change value of the existing A vector and B vector and the changeable (user input value) Alpha. Expressing this as a formula, it can be expressed as G'=G*Alpha*angle AB. Here, the value of the angle AB is a value in the range of 0<angle AB<360°, and the sign is changed based on 180 degrees. (C) shows the calculation of the new vector value of A' with the vector value of G' and the vector value of F'.

In (D) of FIG. 6, vector B' is calculated in the same way as vector A', and the value of alpha is the same as a user-variable value, and varies depending on the angle between vector B and vector C. If the value of the final A vector is recalculated as the A'' vector and selected as the starting coordinate value of the A' vector, one Inset closed structure vector array can be created.

As described above, the image processing method for error correction of the 3D printer output according to the present invention calculates the cross-sectional area data of the printing object from the original digital data of the printing object, and based on the cross-sectional area data, the output operation of the 3D printer is performed The output of the 3D printer is calculated by calculating the output cross-sectional area data for It has the advantage of improving the precision of

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions may include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

In addition, the above-described method or apparatus may be implemented by combining all or part of its configuration or function, or may be implemented separately.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that it can be done.

Claims (5)

a) calculating cross-sectional area data for an arbitrary layer of the printing object by a computer system from the original digital data of the printing object decomposable into a laminated structure of a plurality of slices;
b) calculating output cross-sectional area data for an output operation of a 3D printer from the calculated cross-sectional area data;
c) correcting an error of the output cross-sectional area data by applying a data correction algorithm to the calculated output cross-sectional area data;
d) calculating the output cross-sectional area data in which the error is corrected by applying the data correction algorithm; and
e) performing an output operation of the 3D printer based on the output cross-sectional area data for which the calculated error is corrected, a method for correcting an error in 3D printing. In claim 1,
In calculating the cross-sectional area data in step a), in order to extract 2D data for the arbitrary layer by the computer system, 2D drawing data for the layer is generated, a method for correcting an error in 3D printing . In claim 1,
In calculating the output cross-sectional area data in step b), the output cross-sectional area data is divided according to the printing method to be actually output, a method for correcting an error in 3D printing. In claim 1,
The printing method is SLA (Stereolithography Apparatus), a method for correcting an error in 3D printing. In claim 1,
In correcting the error of the output cross-sectional area data by applying the data correction algorithm in step c),
In the case of an image moving away from the inside according to the location of the inside and the outside, which is created through the division between the inside and the outside of the 2D image, an image close to the inside by a preset distance is created. A method for correcting errors in 3D printing, which creates an image moving away from the inside by a distance.

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